Rosairo Davina, Kuyznierewicz Ileana, Findlay Jock, Drummond Ann
Prince Henry's Institute of Medical Research, Clayton, Victoria 3168, Australia.
Reproduction. 2008 Dec;136(6):799-809. doi: 10.1530/REP-08-0310. Epub 2008 Sep 9.
Ovarian follicular growth and differentiation in response to transforming growth factor-beta (TGFB) was investigated using postnatal and immature ovarian models. TGFB ligand and receptor mRNAs were present in the rat ovary 4-12 days after birth and at day 25. In order to assess the impact of TGFB1 on follicle growth and transition from the primordial through to the primary and preantral stages of development, we established organ cultures with 4-day-old rat ovaries. After 10 days in culture with FSH, TGFB1, or a combination of the two, ovarian follicle numbers were counted and an assessment of atresia was undertaken using TUNEL. Preantral follicle numbers declined significantly when treated with the combination of FSH and TGFB1, consistent with our morphological appraisal suggesting an increase in atretic primary and preantral follicles. To investigate the mechanisms behind the actions of TGFB1, we isolated granulosa cells and treated them with FSH and TGFB1. Markers of proliferative, steroidogenic, and apoptotic capacity were measured by real-time PCR. Cyclin D2 mRNA expression by granulosa cells was significantly increased in response to the combination of FSH and TGFB. The expression of forkhead homolog in rhabdomyosarcoma (Foxo1) mRNA by granulosa cells was significantly reduced in the presence of both FSH and TGFB1, individually and in combination regimes. By contrast, the expression of steroidogenic enzymes/proteins was largely unaffected by TGFB1. These data suggest an inhibitory role for TGFB1 (in the presence of FSH) in follicle development and progression.
利用出生后和未成熟卵巢模型，研究了卵巢卵泡对转化生长因子-β（TGFB）的生长和分化反应。出生后4至12天以及第25天时，大鼠卵巢中存在TGFB配体和受体mRNA。为了评估TGFB1对卵泡生长以及从原始卵泡到初级卵泡和窦前卵泡发育阶段转变的影响，我们用4日龄大鼠卵巢建立了器官培养体系。在用促卵泡激素（FSH）、TGFB1或两者组合培养10天后，对卵巢卵泡数量进行计数，并使用末端脱氧核苷酸转移酶介导的缺口末端标记法（TUNEL）评估闭锁情况。当用FSH和TGFB1组合处理时，窦前卵泡数量显著减少，这与我们的形态学评估结果一致，表明闭锁的初级卵泡和窦前卵泡数量增加。为了研究TGFB1作用背后的机制，我们分离了颗粒细胞，并用FSH和TGFB1对其进行处理。通过实时聚合酶链反应（PCR）测量增殖、类固醇生成和凋亡能力的标志物。颗粒细胞中细胞周期蛋白D2 mRNA的表达在FSH和TGFB组合作用下显著增加。在单独或联合使用FSH和TGFB1的情况下，颗粒细胞中横纹肌肉瘤叉头同源物（Foxo1）mRNA的表达均显著降低。相比之下，类固醇生成酶/蛋白的表达在很大程度上不受TGFB1的影响。这些数据表明，（在FSH存在的情况下）TGFB1在卵泡发育和进展中起抑制作用。
